The present application relates to the field of traveling wave grids, and more particularly, to improving movement and control of organic, inorganic and/or biological particles being carried by the traveling wave grids to focus, separate and/or concentrate the particles.
It is desirable to move the particles for a variety of reasons. For example such movement is useful in applications related to, among others, analysis of proteins and DNA fragment mixtures, and methodologies used for processes such as DNA sequencing, isolating active biological factors associated with diseases such as cystic fibrosis, sickle-cell anemia, myelomas, and leukemia, and establishing immunological reactions between samples on the basis of individual compounds. Movement by traveling wave grids is an extremely effective tool because, among other attributes, it does not affect a molecule's structure, is highly sensitive to small differences in molecular charge and mass, and will not damage the cells of biological materials.
Traveling wave grids manipulate particles by subjecting them to traveling electric fields. Such traveling fields are produced by applying appropriate voltages of suitable frequency and phase to electrode arrays of suitable design, such that non-uniform electric fields are generated.
Thus, by use of traveling wave grids, particles are manipulated and positioned at will without physical contact, leading to new methods for focusing, separation and concentration technology.
It has been appreciated, however, that with existing and previously proposed traveling wave grid devices the particles, including organic, inorganic and bio-materials, within the carrier medium, may settle and adhere to the surface of the traveling wave grid due, for example, to Van der Waals bonding, leading to loss in the amount of a sample and compromising long term reliability.